SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '120d91a9a905855aa0be554239b928632af1461ceec8390e84c63229aaa354f1' 
  AND token = 'vBqdEl3EIhefujD3ASb7YfFPagjCPRY+FEhzO/txjVI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}